Figure 2 - uploaded by Jose Verle Rodrigues
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Native cacti species Pilosocereus royenii, Melocactus intortus and Leptocereus quadricostatus infested with Hypogeococcus pungens in Guánica, PR.
Source publication
The introduction of Harrisia cactus mealybug (HCM), Hypogeococcus pungens, in Puerto Rico causes concern due to its damaging effects to the structure of cacti communities, eliminating species, and severely compromising plant growth and reproduction of susceptible native species. HCM is a polyphagous soft scaly insect considered an aggressive pest o...
Contexts in source publication
Context 1
... 27 days from an initial infestation event. We observed that each initial colony had an average of 0.67 ± 0.6 (n=6) reproductive females per colony with a maximum of 3 reproductive females per colony. An exponential growth model best explains the initial colonization stage by HCM on L. quadricostatus. (R 2 =0.93, F=125.4, df=1,9, p-value < 0.05; Fig. 2). In this study in a controlled environment, the only limitation for HCM to continue growth was the progressive reduction of availability of proper sites for establishment of the colonies (areole availability). HCM colonization takes place in the cactus areoles, if there aren't new areoles available there cannot be new establishment or ...
Context 2
... The bud grows multiple small ramifications that are densely packed forming a type of rounded tumor or gall. The density of spines in the areole is higher than in non-infested cacti. (Fig. 4-2A, 4-2B). 3. The bud elongates as a thin and deformed "branch" which later starts to show multiple branching at the apex of the new branch while gall growth develop similar to type 2 galls (Fig. 4-3A, 4-3B). 4. As a result of the initial curling of the branch, the branch continues to curl. The infested areole that initiated the curling ...
Citations
... (Portulacaceae) (J. C. V. Rodrigues, unpublished data), and on Leptocereus quadricostatus (Cactaceae) (La Quay- Velázquez et al. 2015). Harrisia cactus mealybug colonies then were used for rearing the Leptomastidea sp. ...
Parasitoids, both primary and secondary (hyperparasitoids), of Hypogeococcus spp. mealybugs (Hemiptera: Pseudococcidae) are reviewed to report results of the surveys in the New World conducted during 2009 to 2017 for prospective natural enemies of the Harrisia cactus mealybug, Hypogeococcus sp., which is devastating native cacti in Puerto Rico and threatening cacti in the adjacent Caribbean islands. Five species of Encyrtidae (Hymenoptera: Chalcidoidea) are recorded as primary parasitoids of Hypogeococcus spp., including the newly described Leptomastidea hypogeococci Triapitsyn sp. n., which is the only species of the genus Leptomastidea García Mercet in the New World where the clava of the female antenna is contrastingly white. Genetic analysis of the individuals of L. hypogeococci from Argentina, Brazil, and Puerto Rico (USA) corroborates the morphological data that the same species occurs in South America, the Caribbean islands, and Florida (USA). A key to the New World species of Leptomastidea is given and taxonomic notes are provided on its other known species in the Neotropical region. Leptomastidea antillicola Dozier, syn. n. from Puerto Rico is synonymized under L. abnormis (Girault). Based on the presented molecular data, Anagyrus ciomperliki Triapitsyn syn. n. (Encyrtidae), originally described from Puerto Rico, is synonymized under A. quilmes Triapitsyn, Logarzo & Aguirre, where the known distributional range is expanded to also include Brazil. Anagyrus cachamai Triapitsyn, Logarzo & Aguirre, A. lapachosus Triapitsyn, Aguirre & Logarzo, and A. quilmes are newly recorded from Paraguay. The previously unknown male of Prochiloneurus argentinensis (De Santis) (Encyrtidae) is described from Misiones Province of Argentina, and that of P. narendrani Noyes & Triapitsyn is described from Mona Island, Puerto Rico. So far, Anagyrus cachamai and A. lapachosus are considered to be the primary target species for introduction from Argentina and Paraguay into Puerto Rico for the biological control of Harrisia cactus mealybug. The holotype of Anagyrus tanystis De Santis from Buenos Aires, Argentina, host associations are unknown, and is illustrated to facilitate its recognition from other congeneric species.
Diaspis echinocacti (Bouché, 1833) (Hemiptera: Diaspididae) is a pest insect that can be responsible for gall formation in cactus (Cereus sp.). The process of gall formation in cactus is not fully understood, and there are few studies available on the interaction of D. echinocacti with the cactus plant. Therefore, the aim of this study was to identify morphophysiological changes in the tissues of Cereus sp. infested with D. echinocacti. We performed histological and ultrastructural analyses and UV/Vis spectrophotometry. Gall formation was only observed in plants infested naturally with D. echinocacti. During histological analysis of the gall samples, we observed the formation of a suber region, interspersed with parenchymal cells and cells with lignified walls. Additionally, there was an increase in xylem conductor bundles and an absence of palisade parenchyma cells. Physiologically, the levels of flavonoids in the gall tissues were reduced compared to those in the control. Our data suggest that D. echinocacti may plays a role in gall formation and triggers cell and physiological changes in infested Cereus species.
